58 lines
837 B
Plaintext
58 lines
837 B
Plaintext
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:- object(date(_Year, _Month, _Day)).
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:- info([
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version is 1.0,
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authors is 'Paulo Moura',
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date is 1998/3/23,
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comment is 'Dates as parametric objects.',
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parnames is ['Year', 'Month', 'Day']]).
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:- public(year/1).
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:- mode(year(?integer), one).
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:- public(month/1).
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:- mode(month(?integer), one).
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:- public(day/1).
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:- mode(day(?integer), one).
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:- public(today/0).
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:- mode(today, one).
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:- public(leap_year/0).
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:- mode(leap_year, zero_or_one).
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year(Year) :-
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parameter(1, Year).
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month(Month) :-
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parameter(2, Month).
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day(Day) :-
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parameter(3, Day).
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today :-
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{lgt_current_date(Year, Month, Day)},
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parameter(1, Year),
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parameter(2, Month),
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parameter(3, Day).
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leap_year :-
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parameter(1, Year),
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(0 is mod(Year, 4),
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0 is mod(Year, 100)
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;
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0 is mod(Year, 400)),
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!.
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:- end_object.
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